Unify /usr/bin and /usr/sbin (Fedora 42 Change)

We will likely need to adapt ostree/rpm-ostree for this change in Fedora:

• https://fedoraproject.org/wiki/Changes/Unify_bin_and_sbin
• https://bodhi.fedoraproject.org/updates/FEDORA-2024-3aafcac6a8#comment-3606693
• Tracked for Fedora CoreOS in:
  • https://github.com/coreos/fedora-coreos-tracker/issues/1714#issuecomment-2223100778
  • https://github.com/coreos/fedora-coreos-tracker/issues/1759

The current plan for package mode Fedora is:

Proposal owners:

• Adjust %_sbindir in /usr/lib/rpm/macros (part of rpm package) to evaluate to %_bindir. Packages will be updated automatically during the mass rebuild.
• Add a %filetrigger to filesystem package to create symlinks to ../bin/foo for every foo that is uninstalled from /usr/sbin.
• Add a %posttrans trigger to filesystem package to check that /usr/sbin only contains symlinks and do ln -fs bin /usr/sbin. (Those scriptlets make it easier to have a smooth transition. At all times, the old paths will still work. After the transition is complete we can drop the scriptlets and provide the /usr/sbin symlink in the filesystem package.)
• Adjust systemd package to build with -Dsplit-bin=no.
• File a pull request for Packaging Guidelines to stop mentioning %{_sbindir}. The macro will remain defined to avoid breakage of packages which use it.

Which will likely not work for us.